1. Field of the Invention
This invention relates to a vacuum cleaner whose sucking force is controlled.
2. Description of the Prior Art
A vacuum cleaner is known, whose sucking force is set to about four degrees in accordance with a detected amount of dust. There is another type of a vacuum cleaner whose sucking force is set to some degrees in accordance with a floor surface condition, such as a kind, for example, a woody floor, or straw matting, and length of piles of a carpet. However, it distinguishes a floor surface into only about three degrees.
In the above-mentioned prior art there is a problem as follows:
The amount of dust on the floor and the condition of the floor cannot be distinguished into three or four degrees but it changes continuously. Thus, the sucking force should be set to a lot of degrees. However, in the above-mentioned prior art, the sucking force cannot be set optimally in accordance with the amount of dust and the condition of the floor.